BREEDING 203 



the first variety of fruit originated in North America, 

 was produced by hand-crossing. Nearly all the numer- 

 ous varieties produced by E. W. Durand, of Irvington, New 

 Jersey, between 1865 and 1880 were the result of hand- 

 crossing. At present, most strawberry breeders practice 

 hand-pollination ; it is the only way to be sure of results. 

 Hand-crossing. The work may be done in the field 

 or in the greenhouse. Most of those who breed straw- 

 berries extensively find it best to work with potted plants 

 in the greenhouse or in cold frames, because conditions 

 can be controlled more perfectly than in the field and the 

 crossing can be done when other work is not pressing. 

 Strong plants in six inch pots are brought into bloom, 

 and the number of blossoms on a fruit stalk reduced to 

 five or six. 1 Before these have expanded fully the anthers 

 are cut off while still unopened, using a sharp scalpel or 

 small scissors. Some prefer to pull off the anthers with 

 tweezers. It is best not to mutilate the blossoms, except 

 to cut off the anthers ; the petals and sepals should not 

 be cut. Be careful that none of the anthers lodge in the 

 blossoms. If the seed-bearing parent is a pistillate vari- 

 ety, it is important to cut out all the rudimentary sta- 

 mens ; frequently these are half hidden and inconspicu- 

 ous, but produce enough pollen to vitiate the results. 

 Many pistillate varieties, as the Crescent, produce enough 

 pollen to use for crossing. If there are staminate varie- 

 ties near, other than the one to be used as a pollinizer, 

 it is necessary either to isolate all emasculated plants or 

 to cover each fruit stalk with a paper sack, after it has 

 been prepared for pollination. These are preferably 

 of tough, oiled, tissue paper, but ordinary manila sacks 



1 The methods of forcing strawberries are detailed in " Straw- 

 berry-Growing," Chapter XIII. 



